Dialog or commentary can be a critical audio element in a movie soundtrack or in a television broadcast program. During certain passages of a movie, a listener may desire dialog audio to be more prominent than is provided in an original mix of dialog and non-dialog audio signals. More prominent dialog can be desirable to achieve or maintain listening comfort, such as for a listener with hearing loss, for a listener attempting to understand dialog occurring in other than his or her native language, or under adverse listening conditions.
For some genres or types of media content, such as a sports or game broadcast in which dialog audio is a commentary track, a preferred relationship or ratio of a dialog audio level to a non-dialog audio level can vary significantly from person to person. A preferred audio signal relationship for a particular listener can be, for example, an increase or a reduction in dialog salience, or dialog signal amplitude level, such relative to an original mix or broadcast signal mix.
An audio program can include multiple different audio channel signals. For example, in a conventional multichannel digital audio format, such as the 5.1 format, each of multiple different audio channels can be assigned to a respective playback loudspeaker in a prescribed layout. In a conventional system, a given audio channel signal can include a combination of dialog and non-dialog components in the same signal. Dialog detection or classification techniques can be used to selectively process dialog-related components of the signal.
In an object-based digital audio format, each of multiple different audio signals can be provided independently, such as for rendering at or near a playback location. Such an object-based format can provide more flexibility over a traditional multichannel format, and can make it possible to separately store, process, or transmit different components of an audio program.
For example, in an object-based digital audio format, dialog signals can be handled or processed independently from other audio signals. Furthermore, in object-based digital audio, a signal can include or can be associated with an “object type” designation, such as “dialog”, “music”, “effect”, or some other designation. In some examples, an object signal can refer to a stem of an audio program, such as a music stem, an effects stem, or a dialog stem. Each stem can include one or more audio object signals. Object type information can optionally be embedded or included in metadata with an audio object signal itself. At playback, each audio object signal can optionally be analyzed and processed independently, such as before being mixed and rendered to an output.